/*
   * drivers/pci/rom.c
   *
   * (C) Copyright 2004 Jon Smirl <jonsmirl@yahoo.com>
   * (C) Copyright 2004 Silicon Graphics, Inc. Jesse Barnes <jbarnes@sgi.com>
   *
   * PCI ROM access routines
   */

  #include <linux/kernel.h>
  #include <linux/pci.h>

  #include <linux/slab.h>

  
  #include "pci.h"
  
  /**
   * pci_enable_rom - enable ROM decoding for a PCI device

   * @pdev: PCI device to enable

   *
   * Enable ROM decoding on @dev.  This involves simply turning on the last
   * bit of the PCI ROM BAR.  Note that some cards may share address decoders
   * between the ROM and other resources, so enabling it may disable access
   * to MMIO registers or other card memory.
   */

  int pci_enable_rom(struct pci_dev *pdev)

  {

  	struct resource *res = pdev->resource + PCI_ROM_RESOURCE;
  	struct pci_bus_region region;

  	u32 rom_addr;

  	if (!res->flags)
  		return -1;
  
  	pcibios_resource_to_bus(pdev, &region, res);

  	pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);

  	rom_addr &= ~PCI_ROM_ADDRESS_MASK;
  	rom_addr |= region.start | PCI_ROM_ADDRESS_ENABLE;

  	pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);

  	return 0;

  }
  
  /**
   * pci_disable_rom - disable ROM decoding for a PCI device

   * @pdev: PCI device to disable

   *
   * Disable ROM decoding on a PCI device by turning off the last bit in the
   * ROM BAR.
   */

  void pci_disable_rom(struct pci_dev *pdev)

  {
  	u32 rom_addr;
  	pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr);
  	rom_addr &= ~PCI_ROM_ADDRESS_ENABLE;
  	pci_write_config_dword(pdev, pdev->rom_base_reg, rom_addr);
  }
  
  /**

   * pci_get_rom_size - obtain the actual size of the ROM image

   * @pdev: target PCI device

   * @rom: kernel virtual pointer to image of ROM
   * @size: size of PCI window
   *  return: size of actual ROM image
   *
   * Determine the actual length of the ROM image.
   * The PCI window size could be much larger than the
   * actual image size.
   */

  size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size)

  {
  	void __iomem *image;
  	int last_image;
  
  	image = rom;
  	do {
  		void __iomem *pds;
  		/* Standard PCI ROMs start out with these bytes 55 AA */

  		if (readb(image) != 0x55) {
  			dev_err(&pdev->dev, "Invalid ROM contents
  ");

  			break;

  		}

  		if (readb(image + 1) != 0xAA)
  			break;
  		/* get the PCI data structure and check its signature */
  		pds = image + readw(image + 24);
  		if (readb(pds) != 'P')
  			break;
  		if (readb(pds + 1) != 'C')
  			break;
  		if (readb(pds + 2) != 'I')
  			break;
  		if (readb(pds + 3) != 'R')
  			break;
  		last_image = readb(pds + 21) & 0x80;
  		/* this length is reliable */
  		image += readw(pds + 16) * 512;
  	} while (!last_image);
  
  	/* never return a size larger than the PCI resource window */
  	/* there are known ROMs that get the size wrong */
  	return min((size_t)(image - rom), size);
  }
  
  /**

   * pci_map_rom - map a PCI ROM to kernel space

   * @pdev: pointer to pci device struct

   * @size: pointer to receive size of pci window over ROM

   *
   * Return: kernel virtual pointer to image of ROM

   *
   * Map a PCI ROM into kernel space. If ROM is boot video ROM,
   * the shadow BIOS copy will be returned instead of the
   * actual ROM.
   */
  void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size)
  {
  	struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
  	loff_t start;
  	void __iomem *rom;

  	/*

  	 * IORESOURCE_ROM_SHADOW set on x86, x86_64 and IA64 supports legacy
  	 * memory map if the VGA enable bit of the Bridge Control register is
  	 * set for embedded VGA.

  	 */

  	if (res->flags & IORESOURCE_ROM_SHADOW) {
  		/* primary video rom always starts here */
  		start = (loff_t)0xC0000;
  		*size = 0x20000; /* cover C000:0 through E000:0 */
  	} else {

  		if (res->flags &
  			(IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY)) {

  			*size = pci_resource_len(pdev, PCI_ROM_RESOURCE);

  			return (void __iomem *)(unsigned long)
  				pci_resource_start(pdev, PCI_ROM_RESOURCE);

  		} else {
  			/* assign the ROM an address if it doesn't have one */

  			if (res->parent == NULL &&
  			    pci_assign_resource(pdev,PCI_ROM_RESOURCE))
  				return NULL;

  			start = pci_resource_start(pdev, PCI_ROM_RESOURCE);
  			*size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
  			if (*size == 0)
  				return NULL;
  
  			/* Enable ROM space decodes */

  			if (pci_enable_rom(pdev))
  				return NULL;

  		}
  	}
  
  	rom = ioremap(start, *size);
  	if (!rom) {
  		/* restore enable if ioremap fails */
  		if (!(res->flags & (IORESOURCE_ROM_ENABLE |
  				    IORESOURCE_ROM_SHADOW |
  				    IORESOURCE_ROM_COPY)))
  			pci_disable_rom(pdev);
  		return NULL;
  	}
  
  	/*
  	 * Try to find the true size of the ROM since sometimes the PCI window
  	 * size is much larger than the actual size of the ROM.
  	 * True size is important if the ROM is going to be copied.
  	 */

  	*size = pci_get_rom_size(pdev, rom, *size);

  	return rom;
  }

  #if 0

  /**
   * pci_map_rom_copy - map a PCI ROM to kernel space, create a copy

   * @pdev: pointer to pci device struct

   * @size: pointer to receive size of pci window over ROM

   *
   * Return: kernel virtual pointer to image of ROM

   *
   * Map a PCI ROM into kernel space. If ROM is boot video ROM,
   * the shadow BIOS copy will be returned instead of the
   * actual ROM.
   */
  void __iomem *pci_map_rom_copy(struct pci_dev *pdev, size_t *size)
  {
  	struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
  	void __iomem *rom;
  
  	rom = pci_map_rom(pdev, size);
  	if (!rom)
  		return NULL;

  	if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_SHADOW |
  			  IORESOURCE_ROM_BIOS_COPY))

  		return rom;
  
  	res->start = (unsigned long)kmalloc(*size, GFP_KERNEL);
  	if (!res->start)
  		return rom;
  
  	res->end = res->start + *size;

  	memcpy_fromio((void*)(unsigned long)res->start, rom, *size);

  	pci_unmap_rom(pdev, rom);
  	res->flags |= IORESOURCE_ROM_COPY;

  	return (void __iomem *)(unsigned long)res->start;

  }

  #endif  /*  0  */

  
  /**
   * pci_unmap_rom - unmap the ROM from kernel space

   * @pdev: pointer to pci device struct

   * @rom: virtual address of the previous mapping
   *
   * Remove a mapping of a previously mapped ROM
   */
  void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom)
  {
  	struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];

  	if (res->flags & (IORESOURCE_ROM_COPY | IORESOURCE_ROM_BIOS_COPY))

  		return;
  
  	iounmap(rom);
  
  	/* Disable again before continuing, leave enabled if pci=rom */
  	if (!(res->flags & (IORESOURCE_ROM_ENABLE | IORESOURCE_ROM_SHADOW)))
  		pci_disable_rom(pdev);
  }

  #if 0

  /**
   * pci_remove_rom - disable the ROM and remove its sysfs attribute

   * @pdev: pointer to pci device struct

   *
   * Remove the rom file in sysfs and disable ROM decoding.
   */
  void pci_remove_rom(struct pci_dev *pdev)
  {
  	struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
  
  	if (pci_resource_len(pdev, PCI_ROM_RESOURCE))
  		sysfs_remove_bin_file(&pdev->dev.kobj, pdev->rom_attr);
  	if (!(res->flags & (IORESOURCE_ROM_ENABLE |
  			    IORESOURCE_ROM_SHADOW |

  			    IORESOURCE_ROM_BIOS_COPY |

  			    IORESOURCE_ROM_COPY)))
  		pci_disable_rom(pdev);
  }

  #endif  /*  0  */

  
  /**

   * pci_cleanup_rom - free the ROM copy created by pci_map_rom_copy

   * @pdev: pointer to pci device struct

   *
   * Free the copied ROM if we allocated one.
   */
  void pci_cleanup_rom(struct pci_dev *pdev)
  {
  	struct resource *res = &pdev->resource[PCI_ROM_RESOURCE];
  	if (res->flags & IORESOURCE_ROM_COPY) {

  		kfree((void*)(unsigned long)res->start);

  		res->flags &= ~IORESOURCE_ROM_COPY;
  		res->start = 0;
  		res->end = 0;
  	}
  }
  
  EXPORT_SYMBOL(pci_map_rom);

  EXPORT_SYMBOL(pci_unmap_rom);

  EXPORT_SYMBOL_GPL(pci_enable_rom);
  EXPORT_SYMBOL_GPL(pci_disable_rom);